1. Field of the Invention
The present invention relates to an apparatus and a method for sensing attachment or detachment of a battery in a mobile terminal, and more particularly to an apparatus and a method for sensing attachment or detachment of a detachable external battery in a mobile terminal.
2. Discussion of the Background
Various functions have been added to portable terminals to satisfy various user demands. Particularly, in addition to typical functions, such as email, Internet, and games, a multimedia function to transmit data and video, is often added to the portable terminal.
The various functions of the portable terminal provide users with various conveniences via the portable terminal. However, the addition of functions may also cause the amount of power used by the portable terminal, i.e. the amount of battery consumption, to continuously increase. Therefore, the user may have to charge the battery of the portable terminal more frequently.
In this case, a detachable external battery, which can be attached to and detached from the portable terminal depending on the user's need, may allow a user to avoid the inconvenience associated with having to frequently charge the battery of the portable terminal.
In a portable terminal having a detachable external battery, the external battery and the main body of the portable terminal may be connected to each other through three connector nodes.
Two of the three connector nodes may be used to charge the external battery, and the remaining connector node may be used to determine whether the external battery is detached from the portable terminal, i.e. to sense attachment/detachment of the external battery.
In the portable terminal having the detachable external battery, a pull-up voltage may be applied to the connector node that is used to determine whether the external battery is detached from the portable terminal so that a voltage may be observed when the external battery is assembled with the portable terminal.
When the external battery is detached from the portable terminal, the connector node that is used to determine whether the external battery is detached from the portable terminal may be grounded so that a voltage is not observed. As a result, the portable terminal may determine that the external battery is detached therefrom.
However, in such a scheme for sensing detachment of the external battery, it is necessary that a connector of the terminal include three nodes.